The Gut Microbiota in Health and Disease Flashcards
Why is gut microbiota important?
Provides balance within the host between health and disease
What are the factors that affect gut microbiota?
Diet Lifestage Disease Faecal transplant Prebiotics Antibiotics Probiotics Environment
What non-gut diseases is dysbiosis of the microbiota linked with?
Autism Minimal hepatic encephalopathy Familial mediterranean fever Allergy Atherosclerosis Pancreatitis Liver disease Obesity Fibromyalgia Burn injury Diabetes
What features of IBD could affect microbiota?
Antibiotic use Inflammation Diarrhoea Host diet Host genotype
What are probiotics?
Live microorganisms which, when administered in adequate amounts confer a health benefit on the host
What is a prebiotic?
A substrate that is selectively utilised by host microorganisms conferring a health benefit
What are the mechanisms of action for probiotics?
Competition Bioconversions (diet) Production of vitamins Direct antagonism (pathogens) Competitive exclusion Barrier function Reduce inflammation Immune stimulation
What are the health benefits attributed to prebiotics?
Stool bulking + faster gut transit
Reduction in inflammatory markers
Reduced DNA damage + cell proliferation
Probiotic supplementation of infant formula increase bifidobacteria numbers
Increase Ca absorption + bone health pH effect
Induce lower blood glucose rise after meals
Reduce food intake and fat mass
What are bactericidal antibiotics?
Kill bacteria directly
What are bacteriostatic antibiotics?
Prevent bacterial growth
What are broad spectrum antibiotics?
Target many bacteria
What are narrow spectrum antibiotics?
Target specific species
What are consequences of exposure to antibiotics?
Decreased microbial diversity
Opportunity for pathogen colonisation
Pathogen dominated community
C. diff expands occupying empty niches
Overgrowth of c. diff = toxin production, abdominal pain, fever
C. diff spores are resistant to antibiotics
Recurring c. diff infections
How does a faecal microbial transplantation work?
Faecal sample from screening healthy volunteer donor transplanted into recipient
Donor microbiota repopulates large intestine
Displaces c. diff = prevents reinfection
What is the criteria for a healthy donor stool sample?
Sensitive to antimicrobials
‘easy’ to culture
representative of gut commensal bacteria
